Proceedings of the Annual Meeting of the Cognitive Science Society

An explanatory model of ambiguity resolution in human parsing must denve a multitude of preference behaviors from a concise computational framework. One behavior that has been difficult to account for concisely is the preference to interpret an ambiguous phrase as an argument of a predicate, rather than as a modifier that is less integrally related to a phrase (an adjunct). Previous accounts of the argument preference have rehed on assumptions about adjuncts requiring a more complex structure or entaiJing a delay in their mterpretation. This paper explores a more fundamental distinction between arguments and adjuncts—that the numberof potential arguments of a predicate is fixed, while the number of adjuncts for a phrase is unpredictable. This simple difference has important computational consequences withm the competitive attachment model of human parsing. The model exhibits a preference for arguments over adjuncts due to the necessary differences in competitive properties of the two types of attachment site. The competitive differences also entail that adjuncts accommodate more easily than arguments to contextual effects. The model thus provides a concise and explanatory account of these argument/adjunct asymmetries, avoiding the unnecessary structural or interpretive assumptions made within other approaches.